In the past, cargo for air transporation was loaded and moved on pallets. To simplify the buildup, transportation and restraint of cargo, as well as reduce pilferage, shippers are now using enclosed solid walled cargo containers. Many of these containers are of substantial size to take advantage of the widebodied jumbo aircraft. Large solid walled deep sectioned cargo containers have substantial rigidity and a relatively inflexible floor.
Aircraft due to weight/load factors are constructed of lightweight structural elements which are inherently flexible. Accordingly, floor beams of the cargo compartments may deflect substantially under load.
When large solid walled deep sectioned cargo containers are used in aircraft there results a basic incompatibiltiy between the flexible aircraft floors and the relatively inflexible floors of the cargo containers. This incompatibility in the flexure of the two floors results in a concentration of the cargo loads at specific points and along certain lines on the aircraft floor. This point or line of contact load distribution may result in damage to the container or the aircraft floor.